To find the quartiles, we first need to arrange the data in ascending order. Let's continue with our test scores example from before: 70, 75, 82, 88, 90, 92.

Q1: The first quartile, denoted as Q1, represents the point below which 25% of the data falls. To find Q1, we need to locate the median (the middle value) of the lower half of the data. In our example, the lower half is 70, 75, and 82. The median of this lower half is 75.

Q3: The third quartile, denoted as Q3, represents the point below which 75% of the data falls. Similar to finding Q1, we locate the median of the upper half of the data. In our example, the upper half is 88, 90, and 92, and the median is 90.